Small defense cannons are seen in all appearances of Tourian, in Metroid, Metroid: Zero Mission and Super Metroid. They are affixed to the walls and ceilings of the Zebesian Command Center and fire small projectiles at Samus. These cannons seem to lack targeting systems, as they swivel and shoot in entirely random directions, regardless of who or what is nearby. However, this particular attack pattern makes them somewhat unpredictable and dangerous, especially when accompanied with the infinitely spawning Rinkas.
Samus can safely stand on top of the cannons' glowing, circular bases unless they fire a shot directly upwards at her. Their projectiles, although not terribly damaging, are a great nuisance, as a direct hit will often knock Samus into the lava below, along with being capable of destroying her limited number of Missiles.
These mechanisms can be seen in the blueprints for the Future Aurora Complex featured in one of Corruption's preview trailers, and a very similar device known as the Ring Beam Unit is encountered in the Galactic Federation's Bioweapon Research Center in Metroid: Other M; however, these mechanisms fire Rinkas instead of bullets; a possible variation of these devices makes an appearance during the battle against Aurora Unit 313 in Metroid Prime 3: Corruption.
They are only named in the 1986 manga.
- In Super Metroid, if the Cannon's fire is shot with a Missile or Super Missile, both shots will extinguish each other.
- Though never confirmed, it is likely these mechanisms were present within Sector Zero, a replicate of the Tourian base featured in Metroid: Other M.
|Non-hostile|| Aurora Unit 217 • Baby • Dachora • Databot • Etecoon • Fleet Admiral Castor Dane • Fleet Mechanic • Pow • Septogg • Tatori • Tatori, Jr. |
Training Drone • Watchdrone • Work Robot
|Hostiles|| Aazelion • Airthorn • Autom • Big Metroid • Cannon • GMX-04 Halberd-class turret (if provoked) • Polyp • Proboscum |
Puromi • Ring Beam Unit • Ripper II • Samus Eater (Bud) • Seed platform • Unfreezable Metroid • ZipNMEBomber
|Misc.|| Bloatsac • Blueroot Tree (Dark) • Butterflies • Chomper Fish • Durable plantform • Fish • Fungus • Glow Stem • Great Tree |
Massive tentacle • Moth • Parasitic fungus • Protozoan • RedGrass • Sandgrass • Sbug • Scarp • Scatterbug • Tallon fern • Mantha